The scene surrounding 67 Franklin Street in Watertown, Massachusetts where bombing suspect Dzhokhar A. Tsarnaev was captured hiding inside a boat in the backyard is filled with Law Enforcement.Credit: Nicolaus Czarnecki/Metro

After a violent, grueling week, investigators have yet to charge 19-year-old terror suspect Dzhokhar Tsarnaev following his arrest Friday for allegedly carrying out last week's deadly Boston Marathon bombings.

Investigators said yesterday Dzhokhar and his brother Tamarlen Tsarnaev, 26, who was killed in a shootout Thursday night, were likely planning to launch more violent attacks following Monday's attack, as investigators discovered they had an arsenal of deadly weaponry.

However, evidence suggests that the brothers acted alone, and that the city is safe.

Boston Police Commissioner Ed Davis said at a press event yesterday that he's "satisfied there are no explosive devices in the area of Boylston Street," but said Tsarnaev, who is now suspected of killing four and injuring more than 180 people in a series of events since Monday, was in no condition to be interrogated.

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Davis said earlier police discovered at least four unexploded devices including one similar to the two pressure cooker bombs packed with nails and ball bearings used in the twin blasts Monday.

Tsarnaev was arrested Friday night following a 24-hour manhunt and lock down. He was ultimately found hiding in a boat in a Watertown back yard after suffering multiple gunshot wounds. Tamerlan died the night before during a shootout with police that left behind roughly 250 spent shell casings.

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Davis said Tsarnaev is in "critical but stable condition," at Beth Israel Deaconess Medical Center, where a number of bombing victims have also been treated.

A senior law enforcement official yesterday confirmed to NBC that Tsarnaev is suffering from a wound to his throat that has left him unable to talk, and Gov. Deval Patrick on Saturday backed up that claim, saying Tsarnaev was "unable to communicate."

The ethnic Chechens came to the United States 10 years ago. Their parents, who moved back to southern Russia, have said their sons were framed.

A man who calls himself the suspects' father, Anzor Tsarnaev, said Friday that Dzhokhar is "a true angel," and told the Associated Press, “They were set up, they were set up... I saw it on television; they killed my older son Tamerlan." He also said he wanted the judicial system to "investigate everything, who’s right and who’s guilty.”